Dry binder and process for preparing the same



i ii a a as EXAMIN United States Patent 2,995,454 Patented Aug. 8, 1961 "ice within about two hours and reaches after a few days 2,995,454 a crushing strength about equal to that of the anhydrite DRY BINDER AND PROCESS FOR PREPARING THE SAME Egon Hand], Doorneerdelaan 11, Amstelveen,

used (400-600 kg./cm. It adheres better to iron reinforcement than Portland cement and may be used for Netherlands 5 all building purposes, especially for concrete construc- No Drawing. Filed Feb.26, 1957, Ser. No. 642,370 thes and Claims priority, application Netherlands Oct. 12, 1956 AS filler W may h used P It 15 m 11 Cl i ((31, 105 77 the coarse grains andasmall pieces obtained with the breaking of the anhydrite, if desired together with finely The invention relates to a new dry binder, comprisground anhydriteing in physical admixture, a major proportion of anhy- The invention will be explained in more datalls y drite (substantially anhydrous calcium sulphate) and reference to the following Specific example, which is minor proportions of an alkali metal silicate and a nontended as being illustrative Onlyalkali metal salt and also relates to a process for pre- E le paring said binder. 15

It is known in the art to use ground anhydrite in com- Ohe hundred Parts by volume (:100 Parts by weight) bination with various other substances as a binder. It 0t finely ground ahhydrite of which the Particles P has already been proposed to mix the finely ground through a Tyler sieve with 150 meshes or more, are intihydrite with Portland cement, quick lime, limestone, sulmately muted h Parts by Ybhlme Parts by phates or various organic substances, as the finely ground welght) of finely thylded sodium shbate and 5 Parts by anhydrite cannot set without these additions. It has volume (=6 Parts by weight) of hhely divided hydrated also been previously proposed f the preparation of ferrous sulphate. For manufacturing concrete the binder concrete to treat the finely ground anhydrite with soso obtamed 1S sthred wtth water which may eehtam lutions of an alkali metal silicate. Thus, in the United ebbht 10% by s of H2504 Preferably by adding the States Patent No. 2,292,198, a fairly complicated procequwaleht Prbpbtheh of waste sulphuric acid and with ess has been described for preparing concrete from addltleh of 500 Parts by volume Q Sand Pretetably, ground anhydrite, which has been pretreated, preferably of 300 Parts by Volume of Coarse ahhydrlte and 200 at an elevated temperature, with a dilute solution of Parts by volume of finely ground anhydttte- The sodium silicate, whereafter the finely ground anhydrite, Crete btamed setS m t hours and shows after a which by this treatment has been coated with a gel, is filfew days, depehdmg the nature of the anhydrite, tered g and dried or may be directly used in wet a crushing strength between about 400 and about 600 condition. The coated anhydrite may also be mixed with -2 a solution of an alkali metal silicate for preparing con- Wlth the Same results the ferrous sulphate may be crete, which mixture then sets to a hard mass. Evidently Placed other metal ealts, esPeelahy by aluminium, this entire treatment ought to be carried out upon the b Zme and ehmmmm salts in equivalent qhahtt' building site, which is not economical on account of the cost f the apparatus, energy and work However with Having now particularly described and ascertained the these known anhydrites containing binders it is not posnature of my sald myehtloh and in what manner the sible to prepare a concrete for bearing constructions. same 15 to be P f I declare that what I Claim is: The invention provides a dry binder, which may be 40 -M w f may be P stored and packed and shipped in bags, and like Portland cement Shlppe'hm bags eeh MW of between 2 need only be stirred with water cent and 25 percenJ by volume of a finely divided dry The process according to the invention consists in a m ate and ee 2 Percent and 13 P grinding the anhydrite together with a small proportion een Y V0 0 a finely dlvlded Sulphate of a 110 of dry alkali metal silicate, preferably sodium silicate, atkah metal Selected from the gmhmmrsalts and a small proportion of a dry salt of a non-alkali 0 m, ertbu r 1 copper Zlner metal, such as aluminium, ferric or ferrous iron, copper, manganese chrommm and meltehjthe balance bemg zinc, manganese, chromium or nickel. Alternatively the WW occurring unmodified finely ground anhydrite, may be intimately mixed with a 9! 0 the finely ground alkali metal silicate and the finely 5O me for P Parmg a dry binder which ground non-alkali metal salt. In this manner a dry sfsts essentlally of grinding a mlXhlle consisting essenbinder is obtained, which for preparing concrete, is stirred l of between 2 Percent and 25 Percent y Volume of upon the building site with water, if desired with addia dry alkah metal Silicate and between 2 Percent and tion f a suitable fill 25 percent by volume of a non-alkali metal sulphate se- If the process is used for making buildings which must tested j the g f consisting Q Salts of aluminum be resistant against acids, or if the Water is limy, a femc copper Zlhcr mangaheser chr0- small amount of an acid may be added to it.

For acidifying the make-up water any acid may be used. Suitably sulphuric acid is used, and on account of the lower price, preferably waste sulphuric acid. The proportion of the acid to be added to the make-up water is small and amounts to about 10% by weight of H 80 or the equivalent quantity of another acid. The proportions of dry alkali metal silicate and dry metal salts are also small and may vary between 2 and at the utmost 25% by volume.

The new dry binder of the invention has many advantages. Its preparation is very cheap, as its dry constituents merely ought to be ground, without burning or heating and the chemicals used in small proportions are not costly. The concrete prepared with the binder according to the invention sets chemically very rapidly rnium and nickel, the balance being substantially finelyground naturally occurring ,unmodified anhydrite.

3. A process for preparing a dry binder which consists essentially of intimately mixing a mixture consisting essentially of between 2 percent and 25 percent by volume of a finely divided dry alkali metal silicate, and between 2 percent and 25 percent by volume of a finely divided non-alkali metal sulphate selected from the group consisting of salts of aluminum, ferrous iron, ferric iron, copper, zinc, manganese, chromium and nickel, the balance being substantially finely-ground naturally-occurring unmodified anhydrite.

4. A process for the production of concrete which consists essentially of mixing water with a binder consisting essentially of between 2 percent and 25 percent by volume of a finely divided dry alkali metal silicate and between 2 percent and 25 percent by volume of a finely divided sulphate of a non-alkali metal selected from the group consisting of salts of aluminum, ferrous iron, ferric iron, copper, zinc, manganese, chromium and nickel, the balance being substantially finely-ground naturallyoccurring unmodified anhydrite, and allowing the resultant wet mass to stand.

5. A process for the production of concrete which consists essentially of mixing water containing up to about by weight of sulfuric acid with a binder consisting essentially of between 2 percent and 25 percent by volume of a finely divided dry alkali metal silicate and between 2 percent and 25 percent by volume of a finely divided salt of a non-alkali metal selected from the group consisting of sulphates of aluminum, ferrous iron, ferric iron, copper, zinc, manganese, chromium and nickel, the balance being substantially finely-ground naturally-occuring unmodified anhydrite, and allowing the resultant wet mass to stand. 4

6. A process for the production of concrete which consists essentially of mixing water and a filler with a binder consisting essentially of between 2 percent and 25 percent by volume of a finely divided dry alkali metal silicate and between 2 percent and 25 percent by volume of a finely divided salt of a non-alkali metal selected from the group consisting of sulphates of aluminum, ferrous iron, ferric iron, copper, zinc, manganese, chromium and nickel, the balance being substantially finely-ground naturally-occurring unmodified anhydrite, and allowing the resultant wet mass to stand.

7. A process for the production of concrete which consists essentially of mixing together water containing up to about 10 percent by weight of sulfuric acid, a filler, and a binder consisting essentially of between 2 percent and 25 percent by volume of a finely divided dry alkali metal silicate and between 2 percent and 25 percent by volume of a finely divided salt of a nonalkali metal selected from the group consisting of sulphates of aluminum, ferrous iron, ferric iron, copper, zinc, manganese, chromium and nickel, the balancebeing substantially finely-ground naturally-occurring unmodified anhydrite, and allowing the resultant wet mass to stand.

8. A process for the production of concrete which consists essentially of mixing water and coarse grains of anhydrite with a binder consisting essentially of between 2 percent and 25 percent by volume of a finely divided dry alkali metal silicate and between 2 percent and 25 percent by volume of a finely divided salt of a nonalkali metal selected from the group consisting of sulphates of aluminum, ferrous iron, ferric iron, copper, zinc, manganese, chromium and nickel, the balance being substantially finely-ground naturally-occurring unmodified anhydrite, and allowing the resultant wet mass to stand.

9. A process for the production of concrete which consists essentially of mixing together 'water containing up to about 10 percent by weight of sulfuric acid, coarse grains of anhydrite, and a binder consisting essentially of between 2 percent and 25 percent by volume of a finely divided dry alkali metal silicate and between 2 percent and 25 percent by volume of a finely divided salt of a non-alkali metal selected from the group consisting of sulphates of aluminum, ferrous iron, ferric iron, copper, zinc, manganese, chromium and nickel, the balance being substantially finely-ground naturally-occurring unmodified anhydrite, and allowing the resultant wet mass to stand.

10. A process as defined in claim 2, wherein said silicate is sodium silicate.

11. A process as defined in claim 3, wherein said silicate is sodium silicate.

References Cited in the file of this patent UNITED STATES PATENTS 194,629 Vorse Aug. 28, 1877 217,713 Stewart July 22, 1879 326,317 Mixer Sept. 15, 1885 502,096 Heller July 25, 1893 1,442,406 Hennicke Jan.- 16, 1922 2,379,222 Etridge et al. June 26, 1945 2,410,390 Paley Oct. 29, 1946 2,531,496 Bean Nov. 28, 1950 FOREIGN PATENTS 721,318 Great Britain Jan. 5, 1955 

2. A PROCESS FOR PREPARING A DRY BINDER WHICH CONSISTS ESSENTIALLY OF GRINDING A MIXTURE CONSISTING ESSENTIALLY OF BETWEEN 2 PERCENT AND 25 PERCENT BY VOLUME OF A DRY ALKALI METAL SILICATE, AND BETWEEN 2 PERCENT AND 25 PERCENT BY VOLUME OF A NON-ALKALI METAL SULPHATE SELECTED FROM THE GROUP CONSISTING OF SALTS OF ALUMINUM, FERROUS IRON, FERRIC IRON, COPPER, ZINC, MANGANESE, CHROMIUM AND NICKEL, THE BALANCE BEING SUBSTANTIALLY FINELYGROUND NATURALLY OCCURRING UNMODIFIED ANHYDRITE. 